A high-resolution extinction mapping technique for face-on disc galaxies

Faustino Vieira, Helena, Duarte Cabral, Ana ORCID: https://orcid.org/0000-0002-5259-4774, Davis, Timothy A. ORCID: https://orcid.org/0000-0003-4932-9379, Peretto, Nicolas ORCID: https://orcid.org/0000-0002-6893-602X, Smith, Matthew W. L. ORCID: https://orcid.org/0000-0002-3532-6970, Querejeta, Miguel, Colombo, Dario and Anderson, Michael ORCID: https://orcid.org/0000-0001-7237-3488 2023. A high-resolution extinction mapping technique for face-on disc galaxies. Monthly Notices of the Royal Astronomical Society 524 (1) , pp. 161-175. 10.1093/mnras/stad1876

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Abstract

We present a new dust extinction technique with which we are able to retrieve parsec-scale gas surface density maps for entire nearby galaxies. The method measures the dust attenuation in optical bands on a pixel-by-pixel basis against a smoothed, reconstructed stellar distribution. The contribution of foreground light along the line-of-sight is calibrated using dust emission observations, assuming that the dust sits in a layer close to the mid-plane of the face-on galaxy. Here, we apply this technique to M51 (NGC 5194) as a proof-of-concept, obtaining a resolution of 0.14″ (5 pc). Our dust (and gas) surface density map is consistent with independent dust- and CO-based studies at lower resolution. We find that discrepancies between our estimates of surface density and other studies stem primarily from the choice of dust model (i.e. different dust absorption coefficients). When assuming the same dust opacity law, our technique produces surface densities that are consistent with independent studies. This dust extinction technique provides us with gas surface density maps at an unprecedented resolution for full disc coverage studies of nearby galaxies. The resulting well-resolved spatial information opens the possibility for more in-depth examination of the influence of large-scale dynamics (and also stellar feedback mechanisms) on the interstellar medium at parsec-scales, and consequently star formation in nearby galaxies.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	Oxford University Press
ISSN:	0035-8711
Funders:	STFC
Date of First Compliant Deposit:	3 July 2023
Date of Acceptance:	16 June 2023
Last Modified:	12 Apr 2024 01:24
URI:	https://orca.cardiff.ac.uk/id/eprint/160769

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